Electromigration is the phenomenon where current flow in conductors causes a momentum exchange which can, under certain conditions, result in mass transport in the conductor. Conducting material accumulates in some places on a line; voids are also created. In integrated circuits, this mechanism manifests itself in the form of high resistance lines, open circuits and/or whisker growth, which can lead to failures. Screening for the defects which cause electromigration is time consuming, difficult, and inappropriate for VLSI. While the factors contributing to electromigration in 5 micron/Integrated Circuit geometries are reasonably well understood, there is an uncertainty in evaluating VLSI electromigration reliability because of the potential lack of applicability of simple stripe test data to actual VLSI microcircuits. This study examines the effect of crossed thermal gradients on electromigration. Section II reports some thermal modeling of silicon structures that estimated possible gradients. Section III describes a specially designed test vehicle that features an implanted resistor heat source which produces a crossed thermal gradient on electromigration test stripes. Section IV and V discuss the thermal and physical characterization of the test samples. Section VI details the results of accelerated tests which compared lifetimes of test stripes experiencing a realistic crossed thermal gradient with life-times of controls.